/* This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 *
 * http://www.gnu.org/copyleft/gpl.html
 */
package com.l2dot.gameserver.model.zone;

/**
 * Abstract base class for any zone form
 *
 * @author  durgus
 */
public abstract class L2ZoneForm
{
	public abstract boolean isInsideZone(int x, int y, int z);
	public abstract boolean intersectsRectangle(int x1, int x2, int y1, int y2);
	public abstract double getDistanceToZone(int x, int y);
	public abstract int getLowZ();     //Support for the ability to extract the z coordinates of zones.
	public abstract int getHighZ();    //New fishing patch makes use of that to get the Z for the hook
	                                   //landing coordinates.

	protected boolean lineIntersectsLine(int ax1, int ay1, int ax2, int ay2, int bx1, int by1, int bx2, int by2)
	{
		int s1 = sameSide (ax1, ay1, ax2, ay2, bx1, by1, bx2, by2);
		int s2 = sameSide (bx1, by1, bx2, by2, ax1, ay1, ax2, ay1);

		return s1 <= 0 && s2 <= 0;
	}

	protected int sameSide (double x0, double y0, double x1, double y1, double px0, double py0, double px1, double py1)
	{
		int  sameSide = 0;

		double dx  = x1  - x0;
		double dy  = y1  - y0;
		double dx1 = px0 - x0;
		double dy1 = py0 - y0;
		double dx2 = px1 - x1;
		double dy2 = py1 - y1;

		// Cross product of the vector from the endpoint of the line to the point
		double c1 = dx * dy1 - dy * dx1;
		double c2 = dx * dy2 - dy * dx2;

		if (c1 != 0 && c2 != 0)
			sameSide = c1 < 0 != c2 < 0 ? -1 : 1;
		else if (dx == 0 && dx1 == 0 && dx2 == 0)
			sameSide = !isBetween (y0, y1, py0) && !isBetween (y0, y1, py1) ? 1 : 0;
		else if (dy == 0 && dy1 == 0 && dy2 == 0)
			sameSide = !isBetween (x0, x1, px0) && !isBetween (x0, x1, px1) ? 1 : 0;

		return sameSide;
	}

	protected boolean isBetween (double a, double b, double c)
	{
		return b > a ? c >= a && c <= b : c >= b && c <= a;
	}
}
